Biological 'fumigation' of the soil by the use of green manure. Soil born diseases are often suppressed by the use of methyl bromide to sterilise the soil, especially for strawberry cultivation in UK. This chemical will be banned from use after 2008, so there is great pressure to develop an alternative. In USA, brassica biofumigant crops are being used for potatoes, and in Italy improved cultivars have been developed for green manuring. There are a number of different Caliente Mustards available for this use, and a comprehensive description is available from Plant Solutions Ltd. (all on the web site).
It is necessary to chop the plant into small pieces before ploughing into the ground. The plant cells emit a natural gas which helps to destroy various diseases, especially Verticillium dahliae, a fungus that produces 'wilt' in strawberries. The incorporation of 'green manure' into the soil also has the well known advantages like improving soil fertility and structure, the addition of nutrients, aeration and organic matter and organic culture.
DEFRA (the Department for the Environment, Food and Rural Affairs) carries out thousands of research projects, and many of the reports are available for sale. Go to DEFRA.
For further information see Plantsolutions